Driving support apparatus

ABSTRACT

A driving support apparatus includes an image acquisition that acquires a captured image, a calculator that calculates distance and relative speed between a subject vehicle and a following vehicle, and distances and relative speeds between following vehicles; an evaluator that evaluates a degree of risk caused when the subject vehicle changes a lane to the adjacent lane with respect to the following vehicles on a basis of the distances and the relative speeds; and a display controller that creates support information on the degree of risk associated with a lane change in association with road sections based on positions at which the following vehicles are present, and displays a support image in which a created support information is superimposed on the captured image at a corresponding position on the display portion.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on Japanese Patent Application No.2013-245089 filed on Nov. 27, 2013, the disclosure of which isincorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a driving support apparatus thatdisplays an image obtained by imaging a rear side of a subject vehicle.

BACKGROUND ART

A technique in which an adjacent lane on a rear side of a subjectvehicle is imaged by a camera, and driving support information such as aguide line functioning as an indication of whether a lane change isenabled is superimposed on an image acquired by imaging for display hasbeen proposed (for example, refer to Patent Literature 1).

The inventors of the present application have found the followingregarding a driving support apparatus.

In the technique disclosed in Patent Literature 1, the guide linefunctioning as the indication of whether the lane change is enabled isdisplayed on the basis of one closest following vehicle that travels inan adjacent lane on the rear side of the subject vehicle. According tothe technique, since only the guide line corresponding to the closestfollowing vehicle is displayed, when a driver has given up a lane changein front of the closest following vehicle, the indication fordetermining whether the lane change is enabled after that followingvehicle may not be given to the driver in advance. Therefore, after thesubject vehicle is overtaken by the closest following vehicle, thedriver may have to determine whether the lane change is enabled withreference to the guide line corresponding to a subsequent closestfollowing vehicle.

PRIOR ART LITERATURES Patent Literature

Patent literature 1: JP 2006-51850 A

SUMMARY OF INVENTION

It is an object of the present disclosure to provide a techniquedisplaying support information enabling a risk associated by a lanechange to be determined in advance, with respect to multiple followingvehicles.

According to one aspect of the present disclosure, a driving supportapparatus that is communicably connected to an imaging portion thatimages an adjacent lane on a rear side of a subject vehicle, a situationacquisition that acquires information on whether a plurality offollowing vehicles travelling in the adjacent lane on the rear side ofthe subject vehicle are present or not and information on positions ofthe plurality of following vehicles, and a display portion that displaysan image is provided. The driving support apparatus comprises an imageacquisition, a calculator, an evaluator, and a display controller.

The image acquisition acquires a captured image captured by the imagingportion. The calculator calculates distance and relative speed betweenthe subject vehicle and a following vehicle, and distances and relativespeeds between the following vehicles, on a basis of the informationacquired by the situation acquisition. The evaluator evaluates a degreeof risk caused when the subject vehicle changes a lane to the adjacentlane with respect to the following vehicles on a basis of the distancesand the relative speeds calculated by the calculator. The displaycontroller creates support information on the degree of risk associatedwith a lane change in association with road sections based on positionsat which the following vehicles are present on a basis of an evaluationresult of the degree of risk by the evaluator, and displays a supportimage in which a created support information is superimposed on thecaptured image at a corresponding position on the display portion.

According to the driving support apparatus of the present disclosure, itmay be possible to display and impose the support information associatedwith the road sections based on a position at which the multiplefollowing vehicles are present, on the captured image based on thedegree of risk evaluated for the multiple following vehicles that travelin the adjacent lane.

According to the configuration, it may be possible for the driver tograsp the degree of risk associated with the lane change for not onlyone closest following vehicle but also the subsequent following vehiclesin advance.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features and advantages of the presentdisclosure will become more apparent from the following detaileddescription made with reference to the accompanying drawings. In thedrawings:

FIG. 1 is a block diagram illustrating a configuration of a drivingsupport apparatus;

FIG. 2 is a flowchart illustrating a procedure of a risk determinationprocess for a first closest following vehicle;

FIG. 3 is a flowchart illustrating a procedure of a risk determinationprocess for multiple following vehicles;

FIG. 4 is a diagram showing an outline of highlighting;

FIG. 5A is a diagram showing an image captured by a camera;

FIG. 5B is a diagram showing a first display example in which ahighlighted display image is superimposed on the captured image;

FIG. 6A is a diagram showing a second display example in which ahighlighted display image is superimposed on the captured image;

FIG. 6B is a diagram showing a third display example in which ahighlighted display image is superimposed on the captured image; and

FIG. 7 is a diagram showing a fourth display example in which ahighlighted display image is superimposed on the captured image.

PREFERRED EMBODIMENTS FOR CARRYING OUT INVENTION

An embodiment of the present disclosure will be described with referenceto the drawings. The present disclosure is not limited to the followingembodiment, but can be implemented in various modes.

(Description of Configuration of Driving Support Apparatus)

As illustrated in FIG. 1, a vehicle system 1 of an embodiment includes adriving support apparatus 10, and a camera 20, a rear vehicle detector21, a speed sensor 22, a direction indicator switch 23, a display 30,and a speaker 31, which are connected to the driving support apparatus10.

The camera 20 images a rear side of a vehicle (hereinafter, may bereferred to as a subject vehicle 100) to which the vehicle system 1 ismounted. The camera 20 is fitted to, for example, a rearview mirror ofthe subject vehicle 100 or a vehicle side rearward so that mainly onelane in which the subject vehicle 100 is travelling and another lane(hereinafter referred to as an adjacent lane) adjacent to the lane inwhich the subject vehicle 100 is travelling fall within an imaging area.The camera 20 may be fitted to the right or left side of the vehicle.

The rear vehicle detector 21 is an object detection sensor for detectingpresences or positions (relative positions to the subject vehicle 100)of following vehicles that are travelling in the adjacent lane on a rearside of the subject vehicle 100, which is in the imaging area of thecamera 20, for example, due to image recognition of an image from amillimeter wave radar, a laser radar, or a camera. The speed sensor 22detects a speed of the subject vehicle 100, and inputs a detectionsignal to the driving support apparatus 10. The direction indicatorswitch 23 is a switch for operating a direction indicator (also referredto as a turn signal or a blinker) installed in the subject vehicle 100,and outputs a switch signal for operating the direction indicator.

The display 30 is a display device for displaying an image captured bythe camera 20 and support information superimposed on the capturedimage. The display 30 is installed, for example, to a meter panel infront of a driver's seat, or at a position close to an A pillar which iseasily visible from a driver. The speaker 31 is an audio output devicefor outputting a warning sound corresponding to the degree of riskassociated with a lane change.

The driving support apparatus 10 is an information processing apparatus(for example, a microcomputer) mainly including a CPU, a ROM, and a RAMnot shown. The driving support apparatus 10 realizes a function ofdisplaying the support information on the degree of risk associated withthe lane change of the subject vehicle 100. The driving supportapparatus 10 includes a controller 11, a display output portion 12, anda warning sound output portion 13 as a functional configuration forrealizing the function.

The controller 11 determines the degree of risk caused when the subjectvehicle 100 changes the lane to the adjacent lane due to an influence ofmultiple following vehicles detected by image processing on the capturedimage captured from the camera 20 or the rear vehicle detector 21. Thedetermination of the degree of risk is performed by execution of a riskdetermination process (refer to FIG. 2) for a first closest followingvehicle and a risk determination process (refer to FIG. 3) for themultiple following vehicles. A detailed procedure of those processingwill be described later.

The controller 11 creates an image of the support information indicativeof the degree of risk involved in a road section in which each followingvehicle is travelling, on the basis of results of determining the degreeof risk involved in the multiple following vehicles. The image of thesupport information is created as a highlighted display image that issuperimposed on the captured image captured from the camera 20 in aregion corresponding to the road section in which each following vehicleis travelling. When the controller 11 determines that there is anintention of the lane change on the basis of an operating state of thedirection indicator switch 23, the controller 11 outputs the warningsound according to the degree of risk associated with the lane change.The display output portion 12 allows a support image in which an imageof the support information created in the controller 11 is superimposedon the taken captured image to be output to and displayed on the display30. The warning sound output portion 13 audibly outputs the warningsound based on the control of the controller 11 from the speaker 31.

(Risk Determination Process on First Closest Following Vehicle)

A procedure of the risk determination process on the first closestfollowing vehicle will be described with reference to a flowchart ofFIG. 2. The process is repetitively executed by the controller 11 of thedriving support apparatus 10 in a predetermined control cycle.

In S100, the controller 11 calculates a distance and a relative speedbetween a first following vehicle 101, which is closest to the subjectvehicle 100 among the following vehicles traveling in the adjacent lane,and the subject vehicle 100, on the basis of a detection result obtainedfrom the rear vehicle detector 21. For example, the controller 11 mayspecify the positions of the following vehicles reflected on thecaptured image with the use of image recognition of the captured imagecaptured from the camera 20, and calculate the distances between thefollowing vehicles and the subject vehicle 100. In S102, the controller11 determines the degree of risk involved in the first following vehicle101 on the basis of the distance and the relative speed to the firstfollowing vehicle 101 which are calculated in S100, and the speed of thesubject vehicle 100. In this example, the degree of risk is evaluated tobe higher as the distance between the subject vehicle 100 and thefollowing vehicle is shorter, as the relative speed is higher in adirection of bringing the subject vehicle 100 closer to the followingvehicles, or as the speed of the subject vehicle 100 is higher. In thepresent embodiment, it is assumed that the degree of risk is evaluatedwith three levels of the degree of risk 1 (a low level), the degree ofrisk 2 (a middle level), and the degree of risk 3 (a high level). Whenit is determined that the first following vehicle 101 corresponds to thedegree of risk 1 (the degree of risk 1 in S102), the controller 11proceeds to S104. In S104, the controller 11 creates an image of thesupport information corresponding to the degree of risk 1 for the firstfollowing vehicle 101. When it is determined that the first followingvehicle 101 is the degree of risk 2 (the degree of risk 2 in S102), thecontroller 11 proceeds to S106. In S106, the controller 11 creates animage of the support information corresponding to the degree of risk 2for the first following vehicle 101. When it is determined that thefirst following vehicle 101 is the degree of risk 3 (the degree of risk3 in S102), the controller 11 proceeds to S112. In S112, the controller11 creates an image of the support information corresponding to thedegree of risk 3 for the first following vehicle 101.

In S104, S106, and S112, the controller 11 creates an image in which apartial region of the adjacent lane based on a position at which thefirst following vehicle 101 is present is highlighted with a displaymode corresponding to the degree of risk as an image of the supportinformation, in the captured image acquired from the camera 20. In thisexample, the controller 11 creates a highlighted display image of thedisplay mode corresponding to any one of the degree of risks 1 to 3which is the determination result in S102, in a region on the capturedimage corresponding to a region at a predetermined distance from thefirst following vehicle 101 forward in a travelling direction. Thecontroller 11 creates the highlighted display image of the display modecorresponding to the degree of risk 3 in the region of the capturedimage corresponding to a proximity region before and after the firstfollowing vehicle 101 in the travelling direction regardless of thedetermination result in S102. The proximity region may be changed, forexample, according to the relative speed between the subject vehicle 100and the first following vehicle 101, or the vehicle speed of the firstfollowing vehicle 101.

In S108, the controller 11 determines whether the direction indicatorturns on, or not, on the basis of the operating state of the directionindicator switch 23. When the direction indicator is on (YES in S108),the controller 11 proceeds to S110. In S110, the controller 11 outputs apredetermined warning sound corresponding to the degree of risk 2determined in S102 from the speaker 31 through the warning sound outputportion 13. The warning sound generated in this case notifies the driverof a fact that the degree of risk of the middle level is involved in thelane change. When it is determined that the direction indicator is noton in S108 (NO in S108), the controller 11 completes this processing.

In S114, the controller 11 determines whether the direction indicator ison, or not, on the basis of the operating state of the directionindicator switch 23. When the direction indicator is on (YES in S114),the controller 11 proceeds to S116. In S116, the controller 11 outputs apredetermined warning sound corresponding to the degree of risk 3determined in S102 from the speaker 31 through the warning sound outputportion 13. The warning sound generated in this case notifies the driverof a fact that the degree of risk of the high level is involved in thelane change. When it is determined that the direction indicator is noton in S114 (NO in S114), the controller 11 completes the processing.

(Risk Determination Process on Between Multiple Following Vehicles)

A procedure of the risk determination process on between the multiplefollowing vehicles will be described with reference to a flowchart ofFIG. 3. The process is repetitively executed by the controller 11 of thedriving support apparatus 10 in a predetermined control cycle.

In S200, the controller 11 sets a value (n) of a counter for countingthe order of the following vehicles to one. In S202, the controller 11calculates a distance and a relative speed between an n-th followingvehicle and an (n+1)-th following vehicle closer to the subject vehicle100 among the following vehicles traveling in the adjacent lane, on thebasis of a detection result obtained from the rear vehicle detector 21.In this example, the controller 11 may specify the positions of thefollowing vehicles reflected on the captured image with the use of imagerecognition of the captured image acquired from the camera 20, andcalculate the distance between the following vehicles. In S204, thecontroller 11 determines, on the basis of the distance and the relativespeed between the n-th and (n+1)-th following vehicles which arecalculated in S200, and the speed of the subject vehicle 100, the degreeof risk involved in those two following vehicles. In this example, forexample, the degree of risk is evaluated to be higher as the distancebetween the two following vehicles is shorter, as the relative speed ishigher in a direction of bringing the two following vehicles closer toeach other, or as the speed of the subject vehicle 100 is higher. Inthis example, the degree of risk is evaluated with three levels of thedegree of risk 1, the degree of risk 2, and the degree of risk 3. Whenit is determined that the degree of risk is the degree of risk 1 in S204(the degree of risk 1 in S204), the controller 11 proceeds to S206. InS206, the controller 11 creates an image of the support informationcorresponding to the degree of risk 1 in a middle region between then-th and (n+1)-th following vehicles. When it is determined that thedegree of risk is the degree of risk 2 in S204 (the degree of risk 2 inS204), the controller 11 proceeds to S208. In S208, the controller 11creates an image of the support information corresponding to the degreeof risk 2 in the middle region between the n-th and (n+1)-th followingvehicles. When it is determined that the degree of risk is the degree ofrisk 3 in S204 (the degree of risk 3 in S204), the controller 11proceeds to S210. In S210, the controller 11 creates an image of thesupport information corresponding to the degree of risk 3 in the middleregion between the n-th and (n+1)-th following vehicles.

In S206, S208, and S210, the controller 11 creates an image in which aregion of the adjacent lane corresponding to the middle of the n-th and(n+1)-th following vehicles is highlighted with a display modecorresponding to the degree of risk as an image of the supportinformation, in the captured image acquired from the camera 20. In thisexample, the controller 11 creates a highlighted display image of thedisplay mode corresponding to any one of the degree of risks 1 to 3which is the determination result in S206 in a region on the capturedimage corresponding to a region at a predetermined distance from twofollowing vehicles in the middle of the respective following vehicles.The controller 11 creates the highlighted display image of the displaymode corresponding to the degree of risk 3 in the region of the capturedimage corresponding to a proximity region before and after eachfollowing vehicle in the travelling direction regardless of thedetermination result in S206.

In S212, the controller 11 determines whether the degree of riskinvolved in all of the detected following vehicles has been determined,or not. When the following vehicle not yet determined is present (NO inS212), the controller 11 proceeds to S214. In S214, the controller 11counts up the value (n) of the counter by one, and returns to S202. Whenthe degree of risk involved in all of the detected following vehicleshas been determined (YES in S212), the controller 11 completes thisprocessing.

The images of the support information created in the “risk determinationprocess on the first closest following vehicle” (refer to FIG. 2), and“risk determination process on between the multiple following vehicles”(refer to FIG. 3) are superimposed on each other at a correspondingposition on the captured image captured from the camera 20, anddisplayed on the display 30 through the display output portion 12.

(Specific Example of Determination Result of Degree of Risk)

A specific example of a distribution condition of the degree of riskbased on the “risk determination process on the first closest followingvehicle” (refer to FIG. 2), and “risk determination process on betweenthe multiple following vehicles” (refer to FIG. 3) will be describedwith reference to FIG. 4. In a case of FIG. 4, it is supposed that threefollowing vehicles 101 to 103 are travelling in the same direction asthat of the subject vehicle 100 at the rear of a right adjacent lane ofthe subject vehicle 100.

As illustrated in FIG. 4, the highlighting with the degree of risk 3 isallocated to respective regions B, D, F corresponding to proximityregions immediate before and immediate after the respective followingvehicles 101 to 103 in the adjacent lane. Lengths before and after theregions B, D, F are variable, for example, according to the relativespeed to the subject vehicle 100 or another following vehicle, or thevehicle speed of each following vehicle.

It is assumed that the following vehicle 101 closest to the subjectvehicle 100 is determined as the degree of risk 2. In that case, thehighlighting with the degree of risk 2 is allocated to the region Aacross the region B forward from the following vehicle 101. It isassumed that a middle region between the following vehicle 101 and thefollowing vehicle 102 is determined to be the degree of risk 1. In thatcase, the highlighting with the degree of risk 1 is allocated to aregion C corresponding to a clearance between the region B which is theproximity region of the following vehicle 101 and the region D which isthe proximity region of the following vehicle 102.

It is assumed that a middle region between the following vehicle 102 andthe following vehicle 103 is determined to be the degree of risk 3. Inthat case, the highlighting with the degree of risk 3 is allocated to aregion E corresponding to a clearance between the region D which is theproximity region of the following vehicle 102 and the region F which isthe proximity region of the following vehicle 103. A clearance betweenthe region D and the region F is narrower than a total length of thesubject vehicle 100. For that reason, when the lane is chanted and thesubject vehicle 100 enters that clearance, the subject vehicle 100 mayinterfere with the proximity region of the following vehicles 102, 103.In this way, when the clearance of the proximity region between the twofollowing vehicles is remarkably narrow, the highlighting with thedegree of risk 3 is allocated to the clearance.

(Display Example of Highlighted Display Image)

As display examples of the image in which the highlighted display imageis superimposed on the captured image captured from the camera 20,several cases different in an expression method will be described withreference to FIGS. 5A, 5B, 6A, and 6B.

FIG. 5A is an example of the captured image acquired from the camera 20.A part of a body of the subject vehicle 100 is reflected on a left endof the captured image, and a landscape of the adjacent lane of thesubject vehicle 100 is reflected in a right region of the left end. Inaddition, it is assumed that three following vehicles travelling in arow in the adjacent lane at the rear of the subject vehicle 100 arereflected in the captured image. Hereinafter, the three followingvehicles are identified as a first following vehicle 101, a secondfollowing vehicle 102, and a third following vehicle 103 in order fromthe vehicle closer from the subject vehicle 100.

FIG. 5B illustrates a first display example in which a planarhighlighted display image is superimposed on the captured imageillustrated in FIG. 5A. In this case, an expression method of coveringan overall region where the degree of risk is to be displayed on a roadof the adjacent vehicle with a design such as a solid color, hatching ina planar shape, is used. In the highlighted display image, a color, apattern, thickness or transparency of the design is changed according tothe degree of risk, thereby being capable of discriminating the degreeof risk. The highlighted display image is not drawn in portionsoverlapping with the following vehicles in the captured image. Asidefrom the method of expressing the degree of risk for each region in astepwise fashion, a method of continuously expressing the degree of riskwith the use of colors, light and darkness, or the gradation ofthickness may be employed.

Portions (or regions) in which the highlighted display image overlapswith the following vehicles in the captured image are determined byrecognizing the shape of the following vehicles due to the imagerecognition.

FIG. 6A illustrates a second display example in which a linearhighlighted display image is superimposed on the captured imageillustrated in FIG. 5A. In this case, an expression method in which aregion of the degree of risk is expressed by drawing line segments suchas solid lines, dotted lines, or dashed lines in parallel to each otheralong a road surface, at a front end and a rear end of the region inwhich the degree of risk is to be displayed on the road surface of theadjacent lane is employed. FIG. 6B illustrates a third display examplein which a linear highlighted display image is superimposed on thecaptured image illustrated in FIG. 5A. In this case, an expressionmethod in which a region of the degree of risk is expressed by drawinglines such as solid lines, dotted lines, or dashed lines along both sideends (boundary of the adjacent lane) of the region in which the degreeof risk is to be displayed on the road surface of the adjacent lane isemployed. In more detail, the highlighted display image is drawn as linesegments parallel to each other along white lines for separating thelanes drawn on the road surface. In the highlighted display imagesillustrated in FIGS. 6A and 6B, a color, a thickness, or a design (solidline, dotted line, dashed line) of the lines is changed according to thedegree of risk, thereby being capable of discriminating the degree ofrisk. Those highlighted display images are not drawn in portionsoverlapped with the following vehicles in the image.

FIG. 7 illustrates a fourth display example in which a highlighteddisplay image is superimposed on a captured image different from that inFIG. 5A. In this case, it is assumed that a situation in which afollowing vehicle is present in a blind spot which falls outside aregion captured by the camera 20 in the adjacent lane immediately nextto the subject vehicle 100. For example, in a process where the firstfollowing vehicle 101 overtakes the subject vehicle 100 from thesituation illustrated in FIG. 5A, a situation in which the firstfollowing vehicle 101 falls outside the captured image of the camera 20corresponds to this above case. In this case, when a region high in thedegree of risk deriving from the following vehicle which falls outsidethe captured image remains in the display area, the highlighted displayimage representing a state in which the degree of risk is high issuperimposed and displayed on the captured image. In this situation,when the highlighted display image deriving from the following vehiclethat is present outside of the display area is displayed, a warning markM1 indicating that the following vehicle is present outside of thedisplay area is displayed.

When a white line for distinguishing the lanes from each other is notdetected on a road surface, a region having a predetermined size or aline segment having a predetermined length may be displayed as thesupport information. In this case, the region having the predeterminedsize or the line segment having the predetermined length may be definedby a line segment obtained by plotting average appearance of theadjacent lane displayed on the captured image. Alternatively, the regionhaving the predetermined size or the line segment having thepredetermined length may be defined by a width of the following vehiclestravelling in the adjacent lane displayed on the captured image.

(Modifications)

When it is determined that the direction indicator operates in S108 andS114 of the risk determination process (refer to FIG. 2) on the firstclosest following vehicles, the display mode of the highlighted displayimage that is superimposed and displayed on the captured image may bechanged. Specifically, a color of the highlighted display image may bechanged or flickered during the operation of the direction indicator tohighlight the display more than usual. According to this configuration,when the driver intends to change the lane, the driver can easilyrecognize the risk associated with the lane change.

In the display examples of FIGS. 5A, 5B, 6A, and 6B, the highlighteddisplay image corresponding to the degree of risk of the respectivelevels from the region high in the degree of risk to the region low inthe degree of risk is displayed. Alternatively, the highlighted displayimage may be displayed in the region high in the degree of risk, andnothing may be displayed in the region low in the degree of risk.

According to the vehicle system 1 of the embodiment, the followingeffects are obtained.

It may be possible to superimpose and display the highlighted displayimage that can discriminate the degree of risk associated with the lanechange on the captured image acquired from the camera 20, on the basisof the risk evaluated for the multiple following vehicles travelling inthe adjacent lane. It may be possible to display the highlighted displayimage in association with the proximity regions before and after therespective following vehicles or the regions between the followingvehicles. According this configuration, it may be possible for thedriver to grasp the degree of risk associated with the lane change fornot only one closest following vehicle but also the subsequent followingvehicles in advance.

It may be possible to generate the warning sound corresponding to thedegree of risk or to change the display mode of the highlighted displayimage, on the basis of the operation of the direction indicator.According to the configuration, when the driver intends to change thelane, it may be possible for the driver to clearly grasp the riskassociated with the lane change.

The camera 20 corresponds to an imaging portion of the presentdisclosure. The rear vehicle detector 21 corresponds to a situationacquisition of the present disclosure. The display 30 corresponds to adisplay portion of the present disclosure. The controller 11 and thedisplay output portion 12 correspond to a display controller of thepresent disclosure. S100, S200, and the controller 11 correspond to acalculator of the present disclosure. S102, S204, and the controller 11correspond to an evaluator of the present disclosure. S108, S114, andthe driving support apparatus 10 correspond to an operation determinerof the present disclosure.

According to one aspect of the present disclosure, a driving supportapparatus that is communicably connected to an imaging portion thatimages an adjacent lane on a rear side of a subject vehicle, a situationacquisition that acquires information on whether a plurality offollowing vehicles travelling in the adjacent lane on the rear side ofthe subject vehicle are present or not and information on positions ofthe plurality of following vehicles, and a display portion that displaysan image is provided. The driving support apparatus comprises: an imageacquisition that acquires a captured image captured by the imagingportion; a calculator that calculates distance and relative speedbetween the subject vehicle and a following vehicle, and distances andrelative speeds between the following vehicles, on a basis of theinformation acquired by the situation acquisition; an evaluator thatevaluates a degree of risk caused when the subject vehicle changes alane to the adjacent lane with respect to the following vehicles on abasis of the distances and the relative speeds calculated by thecalculator; and a display controller that creates support information onthe degree of risk associated with a lane change in association withroad sections based on positions at which the following vehicles arepresent on a basis of an evaluation result of the degree of risk by theevaluator, and displays a support image in which a created supportinformation is superimposed on the captured image at a correspondingposition on the display portion.

According to the driving support apparatus of the present disclosure, itmay be possible to superimpose and display the support informationassociated with the road sections based on the positions at which themultiple following vehicles are present on the captured image, on thebasis of the degree of risk evaluated for the multiple followingvehicles that travel in the adjacent lane. According to theconfiguration, it may be possible that the driver grasps the degree ofrisk associated with the lane change for not only one closest followingvehicle but also the subsequent following vehicles in advance.

The flowchart or the process in the flowchart disclosed in thisapplication is formed of multiple sections (or which are referred to assteps), and for example, each section is represented by S100. Eachsection can be divided into multiple sub-sections, and in contrast,multiple sections can also be combined into one section.

In addition, each of the aforementioned multiple sections or acombination thereof can be realized not only as (i) a software sectioncombined with a hardware (a computer, for example) but also as (ii) ahardware section (an integrated circuit or a wired logic circuit, forexample) while including or not including functions of the relateddevices. Furthermore, the hardware section can be configured inside amicrocomputer.

In the present embodiment, paying attention to the functions provided inthe controller 11, the interior of the controller 11 is classified intothe image acquisition, the calculator, the evaluator, and the displaycontroller for convenience, and it is not meant that the interior of thecontroller 11 is physically partitioned into portions corresponding tothe respective “portions”.

While the embodiments, the configurations, and the modes according tothe present disclosure have been described with reference to embodimentsthereof, it is to be understood that the disclosure is not limited tothe embodiments and constructions. The present disclosure is intended tocover various modification and equivalent arrangements. In addition,while the various combinations and configurations, other combinationsand configurations, including more, less or only a single element, arealso within the spirit and scope of the present disclosure.

What is claimed is:
 1. A driving support apparatus that is communicablyconnected to an imaging portion that images an adjacent lane on a rearside of a subject vehicle, a situation acquisition that acquiresinformation on whether a plurality of following vehicles travelling inthe adjacent lane on the rear side of the subject vehicle are present,or not, and information on positions of the plurality of followingvehicles, and a display portion that displays an image, the drivingsupport apparatus comprising: an image acquisition that acquires acaptured image captured by the imaging portion; a calculator thatcalculates distance and relative speed between the subject vehicle and afollowing vehicle, and distances and relative speeds between thefollowing vehicles, on a basis of the information acquired by thesituation acquisition; an evaluator that evaluates a degree of riskcaused when the subject vehicle changes a lane to the adjacent lane withrespect to the following vehicles on a basis of the distances and therelative speeds calculated by the calculator; and a display controllerthat creates support information on the degree of risk associated with alane change in association with road sections based on positions atwhich the following vehicles are present on a basis of an evaluationresult of the degree of risk by the evaluator, and displays a supportimage in which a created support information is superimposed on thecaptured image at a corresponding position on the display portion. 2.The driving support apparatus according to claim 1, wherein: the displaycontroller creates the support information corresponding to the roadsections immediately before and immediately after a position at whicheach of the following vehicles is present; and the display controllerdisplays the support image in which the created support information issuperimposed on the road sections immediately before and immediatelyafter each of the following vehicles, which are reflected on thecaptured image.
 3. The driving support apparatus according to claim 1,wherein: the display controller creates the support informationcorresponding to a road section in a middle region of two continuousfollowing vehicles; and the display controller displays the supportimage in which the created support information is superimposed on aposition of the road section in the middle region of the two continuousfollowing vehicles, which is reflected on the captured image.
 4. Thedriving support apparatus according to claim 1, wherein: the displaycontroller displays, as the support information, the support image inwhich a design of a mode that is capable of discriminating the degree ofrisk associated with the lane change is superimposed on the capturedimage.
 5. The driving support apparatus according to claim 4, wherein:when a white line distinguishing lanes from each other is not detectedon a road surface, the display controller displays a region having apredetermined size or a line segment having a predetermined length asthe support information.
 6. The driving support apparatus according toclaim 5, wherein: the region having the predetermined size or the linesegment having the predetermined length is defined by a line segmentobtained by plotting average appearance of the adjacent lane displayedon the captured image.
 7. The driving support apparatus according toclaim 5, wherein: the region having the predetermined size or the linesegment having the predetermined length is defined by a width of thefollowing vehicles travelling in the adjacent lane displayed on thecaptured image.
 8. The driving support apparatus according to claim 4,wherein: the display controller creates the support information changedin at least one of a color, a pattern, and a transparency of the designof the support information according to the degree of risk associatedwith the lane change; and the display controller draws the supportinformation in a region of the captured image except for a regionoverlapping with the following vehicles.
 9. The driving supportapparatus according to claim 4, wherein: the display controller createsthe support information in which a line segment changed in at least oneof a color, a thickness, and a pattern according to the degree of riskassociated with the lane change is drawn along a road surface in thecaptured image; and the display controller draws the line segment in aregion of the captured image except for regions overlapping with thefollowing vehicles.
 10. The driving support apparatus according to claim4, wherein: the display controller creates the support information inwhich a line segment changed in at least one of a color, a thickness,and a pattern according to the degree of risk associated with the lanechange is drawn along a white line separating lanes on the road surfacein the captured image; and the display controller draws the line segmentin a region of the captured image except for regions overlapping withthe following vehicles.
 11. The driving support apparatus according toclaim 1, further comprising: an operation determiner that determineswhether an operation state of a direction indicator mounted to thesubject vehicle; and a warning portion that outputs a warning soundcorresponding to the degree of risk evaluated by the evaluator to apredetermined sound output portion when the operation determinerdetermines that the direction indicator operates.
 12. The drivingsupport apparatus according to claim 1, further comprising: an operationdeterminer that determines whether an operation state of a directionindicator mounted to the subject vehicle, wherein: the displaycontroller highlights a display mode of the support information when theoperation determiner determines that the direction indicator operates.